Buggy code:
public class Form extends WebMarkupContainer implements IFormSubmitListener { private abstract static class ValidationVisitor implements FormComponent . IVisitor { public void formComponent ( FormComponent formComponent ) { } public abstract void validate ( FormComponent formComponent ) { } } private static final String UPLOAD_TOO_LARGE_RESOURCE_KEY = "uploadTooLarge" ; private static final String UPLOAD_FAILED_RESOURCE_KEY = "uploadFailed" ; private static final short FLAG_SUBMITTED = FLAG_RESERVED1 ; private static final long serialVersionUID = 1L ; private static final Log log = LogFactory . getLog ( Form . class ) ; private Bytes maxSize = Bytes . MAX ; private boolean multiPart = false ; private String javascriptId ; private Object formValidators = null ; private Button defaultButton ; public Form ( final String id ) { } public Form ( final String id , IModel model ) { } public final Button getDefaultButton ( ) { } public Bytes getMaxSize ( ) { } public final void loadPersistentFormComponentValues ( ) { } public final void onFormSubmitted ( ) { } public final boolean isSubmitted ( ) { } protected void internalOnDetach ( ) { } public void removePersistentFormComponentValues ( final boolean disablePersistence ) { } public final void setDefaultButton ( Button button ) { } public void setMaxSize ( final Bytes maxSize ) { } public void setMultiPart ( boolean multiPart ) { } public final Component setVersioned ( final boolean isVersioned ) { } public boolean isVersioned ( ) { } public final void visitFormComponents ( final FormComponent . IVisitor visitor ) { } protected void appendDefaultButtonField ( final MarkupStream markupStream , final ComponentTag openTag ) { String nameAndId = getHiddenFieldId ( ) ; AppendingStringBuffer buffer = new AppendingStringBuffer ( ) ; String value = defaultButton . getModelObjectAsString ( ) ; if ( ( value == null ) || ( "" . equals ( value ) ) ) { value = defaultButton . getMarkupAttributes ( ) . getString ( "value" ) ; } String userAgent = ( ( wicket . protocol . http . request . WebClientInfo ) ( getSession ( ) . getClientInfo ( ) ) ) . getUserAgent ( ) ; buffer . append ( "<input<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"" ) . append ( value ) . append ( "\"<seq2seq4repair_space>name=\"" ) . append ( defaultButton . getInputName ( ) ) . append ( "\"" ) ; if ( ( userAgent != null ) && ( ( userAgent . indexOf ( "MSIE" ) ) != ( - 1 ) ) ) { buffer . append ( "style=\"width:<seq2seq4repair_space>0px\"" ) ; } else { buffer . append ( "<seq2seq4repair_space>style=\"display:<seq2seq4repair_space>none\"" ) ; } <START_BUG> buffer . append ( "\"<seq2seq4repair_space>//>" ) ; <END_BUG> getResponse ( ) . write ( buffer ) ; } protected void beforeUpdateFormComponentModels ( ) { } protected void delegateSubmit ( Button submittingButton ) { } protected final Button findSubmittingButton ( ) { } protected IValuePersister getValuePersister ( ) { } public final boolean hasError ( ) { } protected void internalOnModelChanged ( ) { } protected final void markFormComponentsInvalid ( ) { } protected final void markFormComponentsValid ( ) { } protected final String getHiddenFieldId ( ) { } protected final String getJavascriptId ( ) { } protected void onComponentTagBody ( final MarkupStream markupStream , final ComponentTag openTag ) { } protected void onComponentTag ( final ComponentTag tag ) { } protected void onError ( ) { } protected void onRender ( final MarkupStream markupStream ) { } protected void onSubmit ( ) { } public boolean process ( ) { } protected final void updateFormComponentModels ( ) { } public final void clearInput ( ) { } protected void validate ( ) { } private void validateRequired ( ) { } private void validateConversion ( ) { } private void validateValidators ( ) { } private void validateFormValidators ( ) { } private boolean anyFormComponentError ( ) { } private final boolean handleMultiPart ( ) { } private void persistFormComponentData ( ) { } private void dispatchEvent ( final Page page , final String url ) { } private void inputChanged ( ) { } public final CharSequence getJsForInterfaceUrl ( CharSequence url ) { } class FormDispatchRequest extends Request { private final Request realRequest ; private final String url ; private final Map params = new HashMap ( 4 ) ; public FormDispatchRequest ( final Request realRequest , final String url ) { } public Locale getLocale ( ) { } public String getParameter ( String key ) { } public Map getParameterMap ( ) { } public String [ ] getParameters ( String key ) { } public String getPath ( ) { } public String getRelativeURL ( ) { } public String getURL ( ) { } } public String getValidatorKeyPrefix ( ) { } public void add ( IFormValidator validator ) { } private void formValidators_add ( final IFormValidator validator ) { } private IFormValidator formValidators_get ( int index ) { } private int formValidators_size ( ) { } public final void error ( String error , Map args ) { } }

Fix:
buffer . append ( "<seq2seq4repair_space>//>" ) ;